Audio Echo Cancellation Distortion Detection
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Solution Overview
Problem
Existing acoustic echo cancellation techniques in two-way communication systems, such as videoconferencing, are inadequate in accurately distinguishing between near-end and far-end speech due to distortion introduced by loudspeakers, which affects the performance of double-talk detection units.
Innovation Solution
A conferencing endpoint employs a distortion detection unit and an adaptive filter to isolate and scale distortion energy, which is then used to enhance the accuracy of double-talk detection by comparing energy levels across different frequency spectral regions, ensuring that distortion is not misinterpreted as near-end speech.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If acoustic echo cancellation techniques are used in two-way communication systems, then echo from far-end speech can be reduced, but distortion introduced by loudspeakers causes false detection of near-end speech, reducing double-talk detection accuracy
Solution Approach 1:
A distortion detection unit is introduced as an intermediary component that specifically detects and characterizes loudspeaker distortion. This unit processes the loudspeaker output signal and generates distortion characteristics that are then used by the double-talk detection unit to distinguish between actual near-end speech and distortion artifacts, thereby resolving the detection accuracy problem while maintaining echo cancellation
Solution Approach 2:
The system implements feedback by using the distortion detection unit to continuously monitor loudspeaker output and feed distortion characteristics back to the double-talk detection unit. This feedback loop enables the detection system to adapt to distortion conditions and make more accurate decisions about whether near-end speech is present, preventing false positives while maintaining echo cancellation performance
Data Source
AI summary
A conferencing endpoint includes a loudspeaker, a base microphone, and a double-talk detection module which allows two-way communication between the conferencing endpoint and a remote endpoint only when participants at both endpoints are speaking at the same time, so as to minimize echo due to feedback. The double-talk detection module adds the energy of any distortion from the loudspeaker to the energy of the signal coming from the remote endpoint, and compares this combined energy with the energy of the base microphone to determine whether double-talk is present. The double-talk detection module is thus prevented from mistaking the feedback for near end talk at the endpoint.